Within the art of lighting design there are certain applications which are known to be much more demanding than others; for example, sports and roadway. These more demanding applications typically require, as compared to general purpose lighting, sharper cutoff (i.e., a smaller angle over which light transitions from its maximum candela value (or photometric center) to nearly imperceptible) so to place light on the target area but cut it off before it reaches the stands and produces glare for spectators, as one example. Unfortunately, conventional means of cutting off light such as pivoting or angling of external visors, if done at too steep an angle can have the negative effect of shifting maximum candela of the beam. These more demanding lighting applications require complicated lighting designs wherein the target area is mapped out in a virtual space in lighting design software and each virtual fixture is generated and carefully aimed to a point on the virtual target area so to meticulously build up a virtual lighting design which, in practice, corresponds to an actual lighting design wherein, ideally, a layering of beams from actual lighting fixtures results in a composite beam having the required intensity and uniformity for the application; see, for example, U.S. Pat. No. 7,500,764 incorporated by reference herein in its entirety for additional discussion. The success of the actual lighting design meeting required intensity and uniformity is incumbent upon photometry in the lighting design software matching the light produced by the actual lighting fixtures. Once actual lighting fixtures are installed at the actual target area and cutoff is set using conventional means, candela shift can occur. For example, not all lighting design software is equipped to recalculate beam distribution at high cutoff angles—it is only once installed that fixtures aimed at high cutoff angles will show a detrimental candela shift. Site changes (e.g., trees, new structures) not originally accounted for may necessitate different mounting heights and in situ adjustment of cutoff angles—which could cause candela shift. In practice, candela shift of even one lighting fixture can make an entire lighting design non-compliant for the highest levels of sports.
Of course, there are state-of-the-art lighting fixtures that address many of the needs of demanding lighting applications and to some degree address candela shift; see, for example, U.S. Pat. Nos. 5,887,969 and 8,789,967 incorporated by reference herein in their entirety. However, even within demanding lighting applications like sports and roadway there are still areas having needs unmet or under-met; irregular racetracks and five-pole baseball layouts are two possible examples. In these niche areas of what is referred to as high demand lighting applications circumstances align (e.g., long setbacks with shallow seating, flat tracks, roofless vehicles) such that conventional lighting is inadequate—cutoff is not sharp enough, the beam is not smooth enough, etc.—even when using some of the more advanced lighting technologies discussed in U.S. Pat. Nos. 5,887,969 and 8,789,967. Merely adding additional lenses, visors, baffles, light absorbing material, etc. to a lighting fixture using conventional materials and conventional means—as is standard practice in the industry—does not adequately address the lighting needs of high demand lighting applications; conventional wisdom adds weight and cost, reduces transmission efficiency and light that is useful for the application, and still cannot provide the needed beam control. What is needed is a different approach to lighting design, with commensurate changes to light directing and light redirecting devices.
Thus, there is room for improvement in the art.